Decreased NT-3 plasma levels and platelet serotonin content in patients with hypochondriasis.
OBJECTIVE
Neurotrophins (NT) are a family of closely related proteins, including brain-derived neurotrophic factor, nerve growth factor, neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5). NTs are deemed to regulate several aspects of neuronal survival, development, and function. Although NTs have been associated to a variety of mental disorders, the potential role of NT alterations in hypochondriasis (HC) has never been investigated.


METHODS
In the present study, plasma concentrations of NTs were evaluated in 23 adult patients meeting Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision criteria for HC and 22 healthy controls. Platelet serotonin (5-HT) content was chosen as a measure of serotonergic function. Hypochondriacal symptoms were assessed using the Whiteley Index of Hypochondriasis (WIH).


RESULTS
Plasma NT-3 level (P=.004) and platelet 5-HT (P=.008) were significantly lower in patients with HC compared with controls. Correlation analyses showed that the WIH score was significantly and inversely associated with both NT-3 values (r=-.60, P=.002) and platelet serotonin content (r=-.53, P=.009). We used a multivariate regression model to determine independent predictors of the WIH score. After allowance for potential confounders, plasma NT-3 levels remained the unique independent predictor of the WIH (beta=.003, t=-3.5, P=.003).


CONCLUSIONS
Decreased NT-3 concentration, alongside with serotonin dysfunction, may represent a biological correlate of HC.
Brondino
Natascia
N
Department of Health Sciences, Section of Psychiatry, University of Pavia, Pavia, Italy.
Lanati
Niccolò
N
Barale
Francesco
F
Martinelli
Valentina
V
Politi
Pierluigi
P
Geroldi
Diego
D
Emanuele
Enzo
E
D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D001921:Brain / Q000378:metabolism; D005260:Female; D006801:Humans; D006998:Hypochondriasis / Q000097:blood* / Q000175:diagnosis / Q000523:psychology; D008297:Male; D008875:Middle Aged; D020933:Neurotrophin 3 / Q000097:blood*; D010555:Personality Inventory / Q000706:statistics & numerical data; D011594:Psychometrics; D012016:Reference Values; D012701:Serotonin / Q000097:blood*
D020933:Neurotrophin 3; D012701:Serotonin